1. Technical Field
The present invention relates to an aqueous inkjet recording method and an inkjet recorder ideal for recording on a nonpermeable substrate.
2. Description of the Related Art
Inkjet printers have been widely used as digital signal output equipment in general homes because of having advantages such as low noise, low running cost, and easiness of color printing.
In recent years, inkjet techniques have been increasingly utilized not only in such homes but also for industrial applications such as a display, a poster, and a bulletin board. Since porous substrates used in the industrial applications have problems of durability such as light resistance, water resistance and abrasion resistance, nonpermeable substrates such as plastic films are used and inks therefor are developed.
As such inks, for example, solvent-based inkjet inks using an organic solvent as a vehicle, and ultraviolet curable inkjet inks including a polymerizable monomer as a main component have been ever used widely. However, the solvent-based inkjet inks are not preferable in terms of environmental load because the solvent is evaporated in the atmosphere, and the ultraviolet curable inkjet inks have limited application fields because they may have skin sensitizing properties depending on the monomer to be used and an expensive ultraviolet irradiation apparatus is required to be incorporated to the main body of a printer.
In view of such background, there have been recently developed inkjet inks capable of being directly recordable (printable) on the nonpermeable substrates, which are aqueous inks for inkjet recording which give less environmental load and which have been widely used as inkjet inks for household use. Examples of such known arts are disclosed in Japanese published unexamined applications Nos. JP-2005-220352-A and JP-2001-094082-A.
However, such aqueous inks generally have several drawbacks pointed out in terms of image quality, as compared with the solvent-based inkjet inks.
First, since the ink does not permeate the nonpermeable substrates basically, the ink thereon needs quickly drying, but is difficult to dry due to water as a main solvent of the aqueous ink and a hydrosoluble organic solvent as an additive. Therefore, it is easily conceivable blocking occurs, i.e., the ink transfers to the back of prints when overlapped or rolled.
Many of the nonpermeable substrates have gloss, and an ink capable of giving high gloss is required not to impair uniformity of recorded and unrecorded parts. Different from a solvent ink a resin is dissolved in, the aqueous ink forms a coat film with fusion-bonded particles, and the coat film is likely to have rough surface and less gloss.